Abrasive reamer



May 23, 19 33.

6. w. TYDEMAN ABRASIVE REAMER Filed July 15, 1929 Patented May 23, 1933UNITED STATES CLARENCE w. or anernwoon,

COIiOBADO, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO A. OBERHOLTZ, JR, OFDENVER, COLORADO ABBA SIVE REAMER.

Application filed July 15,

My invention relates to abrasive reamers and is an improvement over myformerinventions applied for August 6th 1928 and September 28th 1928,the serial numbers being 297 ,603 and 308,986 respectively.

' my former inventions there was no quick, positive and reliable methodfor changing the reamer size beyond the range of its adjustment by thesubstitution of shoes or blades of a difi'erent size.

This made it necessary for a shop to have several diiierent sizes ofreamers. There was also no accurate, delicate and reliable adjustment ofthe reamersize in fractions of a thousandth part of an inch which theprecision of the device warranted in actual service, and the shoes orbladeswere not supported for their full'length, which resulted in slightspringing of the shoes or blades when the operator forced the enlargingadjustment too vigorously, resulting in a slightly out of parallel orbellshaped hole. p The object of mypresent invention is to provide anabrasive reamer construction in which shoes or blades of widelydifferent diameter or size may be substituted quickly and conveniently,so that but one reamer is required, in which any desired size of bladesmay be set. r

A further object of my present invention is to provide anabrasive reamerconstruction having a diametral expansion which can be accurately andreliably gauged by a micrometer adjustment to a small fraction of athousandth part of an inch.

A further object of my invention is to provide an abrasive reamer, .theexpanding shoes or blades of which are rigidly supported forsubstantially their entire length so that the reamer will finish a holeexactly parallel even if it is forced or crowded by the workman.

I attain the above objects by (providinga constructionhaving two opposechanneled 1 body being maintained by a fixed tapered 1929. Serialflb.378,332.

shoes or blades adapted to receive sheet abrasive and closely'andslidably fitting for their full lengths upon opposite sides of ataperedcentral body, their position on the cup keyed and longitudinally movableat the small end of the tapered body, and by a resiliently held floatingtapered cup at the large end of the tapered body, and the di-. ameter ofthe hole reamed being adjusted by the position of the shoes along thetapered body as determined by a micrometer adjustment in which theenlargement of the tapered body per inch of length is properly combinedwith the threads per inch and the divisions of an adjusting nut on thethreaded end of the tapered body, thenut bearing against andlongitudinally positioning the solidly held tapered cup against theshoes and the resiliently held tapered cup.

All of this is clearly described below'and isillustrated in the drawing,in which Figure 1 is anelevation in partial section, of my abrasivereamer.

Figure 2 is an elevation in partial section of Figure 1, taken fromabove.

Figure 3 is an end view of one of the shges or blades, as seen from thefloating cup en Figure 4 is a view of the other end of one of the bladesor shoes, that is, as seen from the fixed cup end. v

Figure 5 is an end view of the body.

Figure 6 is an end view, in perspective, of one of the sheet abrasivesin the position it assumes when mounted on a shoe or blade. I

Figure 7 ,is an enlarged fragmenta section of the body on the line 77 ofigure 1, showing a-modified section contour, and in dotted lines showingin an exaggerated way the position of a shoe on the body when inIjoperation. n1 (1 fi v igure 8 is an e arge agmenta' section similar toFigure 7 and showing a ihodi- 90 fied from of'contour for the ta eredfaces 6. The body 1 is provided wit the driving shank 2, which isconnected to the mount- The extenslon of the'small end 8 is providedwith the thread 9 and the keyway 16.

163s such that when the device is set at its The driving shank 2 has ahole for the reception of the pin 11 which fits in the hollow of thewasher 12 and holds it against the pressure of the spring 13.

The spring 13 contacts with thefloating tapered cup 14 and forces itagainst the and the shoes 16 acts to hold that end of the shoes togetherand with their tapered .contact against the tapers 6. of the body 1,-

tapered ends ofthe shoes 16, upon which are mounted the abrasive sheets17, as will be described below. I

The tapered contact between the'cup 14 faces 18 in contact with thetapers 6 of the body 1.

The fixed tapered cup 19 by its contact with the tapered faces 20 of theshoes 16,

acts to hold them together and in contact with the tapers 6 of thebody 1. The sides -16 of the guide channels of the shoes 16 have a closeslidable fit against the fiat sides 5 of the body 1. The key 21 of thefixed on 19 fits in the keyway 10 and is thereby he d from turning withrespect to the body while permitting longitudinal movement of .the cup19 thereon.

The knurled adjusting nut 22 is in close threaded engagement with thethreads 9 of the body 1, and bears against the fixed cup 19, thuspositioning the cup 19, the shoes 16 and the cup 14 against the pressureof the spring 13.

Adjustment of the nut 22 on'the threads 9 adjusts the position of theshoes 16 upon the tapers 6, and thereby adjusts the diameter of the holereamed by the reamer. When it is desired to replace the' shoes withshoesof difierent size, the floating cup .14 is pushed along the shank 2againstthe pressure of the spring 13 till it releases the tapered ends15 of the shoes, which per- .mits the shoes to be withdrawn from thefixed taperedcu 19. The new shoes are put 1n place by rst insertingtheir tapered ends 20 1n the cup 19, bringing the shoes together tillthe body 1 fits into their longi-- tudinalchannels and their taperedfaces 18 and then permitting the spring 13 to push the floatin on 14into place where it holds the tapere en s 15 of the shoes together andholds them firmly upon the tapers 6 of the body 1. g

The sheet abrasives 17 ofthe size corresponding to the shoes or bladesin use, are

mounted upon the shoes or blades 16 by being bent to the position shownin Figure 6, and are then slipped upon the shoes endminimum sizeadjustment with a'certain size of shoe, the main contact on the abrasivewill be at the sides as at A and A ure-7 and as the setting changestoward the maximum size the main contact will move toward the center ofthe shoes as at E and E.

In order that the adjusting nut 22 may act as a delicate and accuratemicrometer gauge for the diameter of hole finished by the reamer, thefollowing construction is used The angle of the tapers 6. of the body 1is such that they separate at the rate of seventy thousandths of an inch(.070") to each axial inch.

The threads 9 have twenty, eight (28) threads to the inch, so that ittakes 28 turns of the nut 22 to enlarge the reamer size seventythousandths of an'inch. Then, one turn of, the nut 22 will open thereamer 1/28th of seventy thousandths, or two and one half thousandths-ofan inch.

- The cup 19 is provided with the zero mark 27 adjacent its contact withthe nut 22, and the nut 22 is divided by the marks 28 into 25 equaldivisions. i

That is, one division is one twenty fifth of a turn for the nut 22, orone twenty fifth of two and a half thousandths, that is, one tenthousandth part of an inch.

As the divisions on the nut 22 are roughly an eighth of an inch apart,this permits a careful'workman to approximate the proper distance fromthe nearest division mark and with fair certainty make an adjustment ofsay one fourth of a division, or one fortieth of a thousandth part of aninch. It is not meant that the ordinary workman can work this close, butthis delicateadjustment does provide means whereby a workman can 'udgehow much to turn the nut 22 when ma ing the last finishing touch to afit, when there is perhaps 'ust a little too imich drag as the pin'ispus ed throughthe It also permits a workman to finish a. hole, note thesetting of the nut 22, reduce the size of the reamer by backing off thenut 22 till the reamer will come out of the hole without .cutting orscratching, and then on the next hole the known former setting willinsure his not adjusting the reamer to a greater size than the precedinhole, if a little care is used, and if he s ould be careless of Figtiredivision it would mean a variation of but one tenth of a thousandth ofan inch in the hole size.

In fitting the pistons and connecting rod ends (when floating pins areused), all of the holes may be roughed out to within a thousandth of aninch of the required size, say, by the aid of this micrometeradjustment, and then the last finishing fit may be easily and quicklymade for pin by individual fitting.

In this connection it may be stated that the life of the abrasives isquite surprising.

In one well known make of V-eight automobile engine, the eight pistonsand the eight rod ends were rough fit to the same micrometer setting,just to note the amount of wear on the abrasives.

It was found that the greatest variation in size, that is, that betweenthelargest hole of the 16 holes, and the smallest hole, was

7 one half'of a thousandth part of an inch.

chosen for the body 1, different The pins on the same engine were thenmeasured and were found to vary from the largest to the smallest by sixtenths of a thousandth part of an inch.

This gives a comparative indication of the extreme accuracy afforded bymy reamer .with this micrometer adjustment and the full length supportsfor the shoes.

I am aware thatdiiferent tapers may be threads per inch may be employedand a different-number of divisions may be marked upon the nut 22, butin any case the result will be the samein that the spread per axial inchof the tapers combinedwith the number of threads per inch of theadjusting nut give the variations in reamer diameter corresponding tothe parts of an inch indicated by the divisions on the adjusting nut.

In Figure 5 it will be seen that when the reamer is turned in thedirection indicated by the arrow, the tapered faces 18 of the body 1,are beveled as at 29; that is the lagging corners are beveled.

The reason for this will be more clearly understood by the exaggeratedview shown in Figure 7.

- In this enlarged view, the rotation as indicatedby the arrow D is inthe same direction as in Figure 5, but the beveled faces 29 are replacedby the faces 30 of curved-contour. 4

. In either case, the main point is that the leadingcorner of thetapered faces 18 is full, and the lagging corner is relieved.

The contour and the amount of this relief may depend upon severalconditions, but the reason for such relief isas follows In myexperiments with my reamer it was found that -if the shoes were .veryclosely fitted upon the body, the reamer worked perfectly, did notchatter nor lock in the hole,

each individual and there was apparently no reason at all to suspectpossible trouble.

But, it was also found, that if, in the course of mass production theshoes were fit the least bit too freely upon the body 1,

a looking or clutch efl'ect, or a chatter was 7 When the reamer isadjusted till contact with the wall of the hole occurs, say at the pointA on the abrasive 17, there is a tendency for the friction thusdeveloped to move the shoe 16 in a direction opposite to the arrow D,with respect to the body 1.

If there is a little play between the body 1 and the shoe 16 thismovement between the two will take place about the point 31, say, as acenter, andthe contact point A will temil to follow the curve B duetothe radius In other words the action is that of a fillitch whichlocks-the reamer tight in the o e. r

If, however, the corner 31 is relievedalmost to the corner 32 as shown,the point A will tend to revolve about the corner 32 as a center withthe radius R and will follow the curve C.

The proportions of Figure 7 aremuch exaggerated, since in actual use thematter concerns at most a few thousandths of an inch, and it is foundthat the corner 31 need not be relieved more than about half way tothecorner 32 under most conditions,- but .the exaggeration only tends tomake-what happens more clear.

With the construction shown in Figure 7 the reamer willoperate perfectlywhen-revolved in the direction of.the arrow D, but will lock tight inthe hole when revolved in the opposite direction.

The diameter of the hole being reamed, the thickness andthe width of thebody 1, and the outer contour of the shoes 16 are all of them factorswhich combine to determine What amount of the lagging corners of thetapered faces of the body 1 should be removed, or how close to theirleading corners the faces 18 should be relieved. This matter ofproportion can be readily deter mined by trial by any intelligentmechanic,

'once he is aware that the lagging corner must be relieved enough toprevent the lock action mentioned, or to prevent chattering.

If it is desired to build a reamer that can be revolved in eitherdirection, then both corners of the taper faces 18 must be consideredlagging corners, since one will be lagging when the reamer is revolvedin one direction, and the other will be lagging when the reamer isrevolved in the other ditouch the sides 6 of the body.

rection.

In this case, with both corners relieved, the tapered faces 18 will bereduced to little more than a line midway between the two corners.

This is illustrated in Figure 8, in which the similar contours 33intersect on the tap ered face 18 in the center of the body 1.

Since this construction from a practical standpoint is slightly moredifficult to make,- and since there is no particular advantage in areamer that may be revolved in either direction, I prefer theconstruction shown in Figures 5 and 7, though any mechanic willappreciate that the construction best suited from all standpoints to theparticular case in hand, should of course be employed.

The followingmay be stated as further explanation of the reason for therelief of the body 1 as at 29 or 30;

If there is any play between the shoe and the body it has been found byactual test that the instrument will chatter or look unless the laggingcorners of the faces 18 are relieved. It can be seen that when thetension is applied and the reamer is snug in the hole the shoe will tendto hang back and twist or cook with respect to the body until the sides16' of the shoe guide channels touch the body sides 5 and the faces 18of the shoes If the play between shoes .nd' body is such asto permitenough of this twisting or cocking movement between them, the clutchefi'ect mentioned above is produced.

My reamer is not necessarily limited to a two blade or shoeconstruction, since any other number of blades may be employed ifdesired, so long as they are supported for substantially their entirelength and are adjusted by a proper micrometer adjustment. So, I do notmean to confine the construction narrowly to a two blade or shoeconstruction.

Actual tests, however, have shown that a two shoe or blade reamer isjust as efficient as one having more shoes or blades and it is of coursecheaper to manufacture.

Having now described my invention, what I claim as new, and desire toprotect by Letters Patent, is as follows.;

1. In an adjustable abrasive hole-finishing cutting tool, a central bodyhaving parallel sides joined by tapered facesi forming a tapered portionhaving a small and a large end and provided with 'a threaded portionextending from the said small end and a driving shank extending from thelarge end, a mounting shank, means forming a universal connectionbetween the mounting shank and the driving shank, a cupon said drivingshank facing said large end, resilient means longitudinally positioningthe cup against the said large end, shoes provided with abrasive membersfitting upon said body and radially positioned by said tapered faces andat the said large end adapted to extend into said cup and be therebyheld upon said body,

a cup on said threaded portion and adapted holding them upon the saidbody, a spring positioned upon the said body and bearing against one ofsaid cups, and an adjustin member threadedly engaging said body anadapted to bear against the other cup.

3. In a, cutting tool having a central ody with faces taperedaredetermined part of an inch per axial inc and shoes provided withabrasive members fitting thereon and contacting, said tapered faces forsubstantially their entire lertiigth, cups fitting the ends of saidshoes an thereby holding the shoes in place on said body, a springpositioned upon the said body and bearing agamst one of said cups tohold it against the shoes, an adjusting member threadedly engaging thesaid body by a predetermined number of threads per inch and in contactwith the other cup and adapted to position it and the shoes against thepressure of the first cup and said spring, the adjusting member andadjacent cup acting as micrometer members, one of which carries an indexmark and the other of which is provided with a plurality of marksequally spaced to combine with the taper of said tapered faces, and thethreads per inch of said engagement between the body and the adjustingmember to indicate a predetermined part of an inch per division ofmovement of one of said micrometer parts with respect to the other..

ly position the other cup, and adjust the diameter of said tool bychange of the axial position of said shoes upon said body against thepressure ofsaid spring.

5. In a cutting tool having a threaded cem tral body with tapered facesand shoes provided with abrasive members fitting thereon,

cups fitting the end of said shoes and thereby holding them upon thesaid body, a spring positioned upon the said body and bearing againstone of said cups, theother cup having a guided axially movableengagement with said body and an adjusting member in threaded engagementwith the threads of said body and bearing against the guided cup, thecup and the adjusting member acting as micrometer members one of whichcarries an index mark and the other of which is provided with aplurality of equally spaced division marks, whereby the movement of theadjusting member one of said divisions combined with the pitch of saidthreads and the angle of said tapered faces will move the shoes axiallyon said body and thereby vary their diameter a predetermined part of aninch.

3.6. In a cutting tool having a threaded central' body with taperedfaces and shoes provided with abrasive members fitting thereon andhaving contact with said tapered faces for substantially the entirelength of said shoes, cones fitting the ends of the said shoes andadapted to thereby hold them upon said body, a spring carried by thebody and hearing against one of said cones, the other cone having aguided axially movable engagement with said body and acting as amicrometer part, and an adjusting member threadedly engaging said bodyand bearing against the guided cone and actmg as another micrometerpart, one of said parts pro vided .with an index mark, and the otherpart provided with a scale of equal divisions, whereby the movement ofsaid adjusting member one division will axiall' move the shoes and varythe tool diameter termined part of aninch.

7. In a cutting tool having a central body with tapered faces,abrasive-supporting shoes internally tapered to fit said tapered facesof the body, two cups 011 the body in contact with the ends of saidshoes and holding them upon said body, a spring supported on said bodyand bearing against one of said cups, and means 'on said bodypositioning the other cup against the pressure of 8. In a cutting toolhaving a central body with two opposed ffaces joined by two substantially parallel faces and having abrasive-supporting shoes fittingthereon, cups internally tapered and fitting over the ends of said shoesmounted upon said body and thereby holding the shoes on the body and aspring positioned upon said body and bear- 1ng agamst one of said cupsto hold'it in resilient contact with the adjacent ends of the saidshoes. r

9. In a cutting tool having a central body with tapered faces and havingan abrasive supporting, bevel-ended shoe fitting upon each tapered face,two internally, tapered, I

tapered side walls, a pair of shoes adjustably mounted on the shank bodyand having inner inclined faces tapered reversely to the tapered facesof the shank body, a nut threaded on said threaded end of the shank, anenlarged annular collar confining the lower ends of the shoes adjustableby said nut, a collar slidable on the upper end of the shank having anenlarged annular flange confining the upper ends of the shoes, a coilspring on the shank engaging the collar, means on the upper end of theshank engaging' the spring to place the same under tension and hold thecollar engaged with the shoes, an abrading sheet inclosing the shoes,alrlid means for retaining the sheeton the s oes.

11, A cutting or abrading tool comprising a body member of substantiallyrectangular cross section, two substantially identical abrasivesupporting shoes, each shoe having a rectangular guide channel extendinglongitudinally thereof, said guide channels being of the proper size toreceive the edges of the body mem er, the body member serving as a meansfor rotating the shoes about its longitudinal axis, the lagging cornersof the body members being chamfered, and means for holding the shoes inplace on the body memr. 12. A cutting or abrading tool comprising a bodymember having a substantially rec-. tangular body portion whose edgesare equally inclined with respect to its longitudinal axis of syminetry,two substantially identical abrasive supporting shoes, each shoe havinga rectangular guide channel whose bottom is inclined with respect to theios beveled edge, abrasive-supporting shoes internally tapered to fitsaid tapered faces and two cups on the body in contact with the ends ofthe shoes and holding them upon said body, the cups being movable in thedirection of the length of the body to posi-- tion the shoes for thepurposeof adjustment and for holding them in adjusted position.

14. In a cutting tool having a central body with tapered faces, eachface having a beveled edge; abrasive supporting shoes fitting upon saidfaces, means for holding the shoes in position on the body member andmeans for adjusting the position of the shoes in the'direction of thelength of the tapered face-t0 adjust the diameter of the tool and forholding the shoes in adjusted position.

In testimony whereof I afiix my signature.

CLARENCE W. TYDEMAN.

